GHRP-2: The One GHRP That’s Actually an Approved Drug
GHRP-2 is the one member of the GHRP family that's actually an approved drug, just not for what most people buy it for. Since 2004, Japan's regulator has approved it, under the name pralmorelin, as a single-dose diagnostic test for growth hormone deficiency, marketed by Kaken Pharmaceutical. A separate US effort to develop it as an ongoing growth-hormone therapy was discontinued after Phase II. Today it's sold in the US as an unregulated research peptide, for a repeated, self-administered use its one real approval was never for.
Reviewed by the PepGuard team · Last reviewed Jul 28, 2026
Synthetic hexapeptide (D-Ala-D-2Nal-Ala-Trp-D-Phe-Lys-NH2), a ghrelin-receptor (GHS-R1a) agonist · also sold as Pralmorelin, KP-102, GPA 748
Photo: National Cancer Institute / UnsplashJapan approved it in 2004. Not for building muscle.
Every other peptide in the GHRP family, hexarelin, GHRP-6, is unapproved everywhere. GHRP-2 broke that pattern: since October 2004, Japan’s regulator has approved it, under the name pralmorelin, marketed as GHRP Kaken 100 by Kaken Pharmaceutical. The approval covers exactly one thing: a single intravenous dose, given once, as a diagnostic test to measure whether a patient’s pituitary gland can release growth hormone at all. It was never approved as an ongoing therapy, and it certainly wasn’t approved for the repeated, self-administered use it’s sold for in the US research-peptide market today.
A separate development path tried to get there. Wyeth held a US sublicense specifically to develop GHRP-2 as a growth-hormone-deficiency treatment, not a diagnostic. Those Phase II trials were discontinued. So the honest picture is this: the one real regulatory approval this compound has ever earned, anywhere, is for a single lab test, not for the thing most buyers actually use it for.
What’s actually been dosed, and to whom.
| What's cited | Range |
|---|---|
| Foundational oral dose-response trial (Bowers et al. 1992, n=5 healthy men + n=9 short-stature children) | 100-300 mcg/kg oral; GH rose 63-fold (100 mcg/kg) to 202-fold (300 mcg/kg) above baseline in adults |
| Pediatric growth trial (Pihoker et al. 1997, n=15 short-stature children, intranasal, 6-24 months) | 5-20 mcg/kg, twice daily initially, escalated to three times daily |
| Appetite-stimulation study dose (Laferrère et al. 2005, n=7 healthy men, subcutaneous infusion) | 1 mcg/kg/hour, infused over 270 minutes |
The foundational human trial used an oral dose and found it barely absorbed, about 0.3% as bioavailable as an equivalent intravenous dose, which is why essentially every other published trial and the Japanese diagnostic protocol use injection instead. Japan's approved diagnostic use is a single standardized intravenous dose administered once as a test, not a repeated dosing schedule; we could not independently verify the exact microgram figure used in that specific protocol from a primary source, so we're not stating one here. The pediatric growth trial and the appetite study below are the two intravenous/subcutaneous protocols we could verify in detail.
Real appetite data, and a safety flag the FDA won’t call conclusive.
| Signal | Frequency | Context |
|---|---|---|
| Increased appetite / food intake | commonly reported | A controlled trial found participants ate roughly 36% more at a buffet meal during a GHRP-2 infusion than during a saline infusion, consistent with its ghrelin-receptor activity. |
| Reduced or absent GH response in some patients | occasionally reported | In the foundational pediatric trial, 5 of 9 short-stature children showed a reduced or undetectable GH response, unlike the healthy adults in the same study. |
| Serious adverse events reported in critically ill patients | rarely reported | FDA states it is aware of reports including increased insulin requirement, death of critically ill study subjects, infection, and pancreatitis, but explicitly notes causality has not been established. |
| Long-term safety of repeated self-administered use | unknown / not studied | Japan's approved use is a single diagnostic dose. No published trial has tested the ongoing, repeated self-administration pattern common in the research-peptide market. |
Not FDA-approved. Approved in Japan for one narrow diagnostic use. The FDA flags it as a 503B substance citing safety concerns.
GHRP-2 has never been approved by the FDA for any use. Wyeth held a US sublicense to develop it as a growth-hormone-deficiency treatment, but those Phase II trials were discontinued. Japan is a different story: since October 2004, Japan's regulator has approved it, under the international nonproprietary name pralmorelin (marketed as GHRP Kaken 100 by Kaken Pharmaceutical), exclusively as a single-dose diagnostic agent for assessing growth hormone deficiency, not as an ongoing therapy, and not for the repeated self-administered use it's actually sold for in the US research-peptide market. In the US, FDA lists GHRP-2 (for injectable and nasal routes) as a 503B substance, added September 29, 2023, citing risk of immunogenicity from aggregation and peptide-related impurities, and stating it "is aware of reports of serious adverse events in patients who received GHRP-2, including increased insulin requirement to maintain the blood glucose level, death of critically ill study subjects, infection and pancreatitis," while explicitly noting causality has not been established. Separately, GHRP-2 is prohibited under the World Anti-Doping Agency's code, with published laboratory methods specifically developed to detect it in urine.
Every claim above, traced back.
Four published human trials, a formal drug-identity review, a US government drug database entry, current FDA compounding records, and a WADA anti-doping detection paper. Click through and check them yourself.
GHRP-2 questions, answered.
Yes, uniquely among this whole peptide family. Japan has approved it, since October 2004, under the name pralmorelin (brand GHRP Kaken 100), but strictly as a single-dose diagnostic test for growth hormone deficiency, not as an ongoing therapy. A separate US effort by Wyeth to develop it as a growth-hormone treatment was discontinued after Phase II, and it has never been approved by the FDA.
They're close chemical relatives in the same GHRP family, and the FDA treats them differently: FDA's bulk-substances list cites specific reported adverse events for GHRP-2 that it doesn't cite for hexarelin, which doesn't appear on FDA's current compounding lists at all. See our Hexarelin report for that comparison from the other side.
Yes. It's prohibited under the World Anti-Doping Agency's code, and anti-doping laboratories have published validated methods specifically for detecting GHRP-2 and its metabolite in urine.
FDA states it's aware of reports of serious adverse events in patients who received GHRP-2, including increased insulin requirement, death of critically ill study subjects, infection, and pancreatitis, though it explicitly notes causality hasn't been established. Separately, a foundational pediatric trial found the GH response was reduced or absent in over half the short-stature children tested. Japan's one approved use is a single diagnostic dose, not a repeated self-administered protocol, and no trial has tested the safety of that kind of ongoing use.
Keep researching.
This is a preview of the GHRP-2 report.
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